Energy release from hadron-quark phase transition in neutron stars and the axial $w$-mode of gravitational waves

TL;DR

This paper investigates the energy released during the hadron-quark phase transition in neutron stars and analyzes how this transition affects the axial $w$-mode gravitational waves, highlighting the influence of the bag constant.

Contribution

It introduces a combined model for hyperonic and quark phases in neutron stars and studies the impact of the phase transition on gravitational wave properties.

Findings

Energy release is highly sensitive to the bag constant.

The $w$-mode frequency varies significantly with the phase transition.

Density dependence of symmetry energy affects results at high bag constants.

Abstract

Describing the hyperonic and quark phases of neutron stars with an isospin- and momentum-dependent effective interaction for the baryon octet and the MIT bag model, respectively, and using the Gibbs conditions to construct the mixed phase, we study the energy release due to the hadron-quark phase transition. Moreover, the frequency and damping time of the first axial $w$-mode of gravitational waves are studied for both hyperonic and hybrid stars. We find that the energy release is much more sensitive to the bag constant than the density dependence of the nuclear symmetry energy. Also, the frequency of the $w$-mode is found to be significantly different with or without the hadron-quark phase transition and depends strongly on the value of the bag constant. Effects of the density dependence of the nuclear symmetry energy become, however, important for large values of the bag constant that lead to higher hadron-quark transition densities.